1. Field of the Invention
The present invention relates to a container for receiving and transporting an article such as a substrate necessary to be kept under the condition of high cleanliness during being transported. There is described hereunder a container in relation to a semiconductor substrate such as a silicon wafer or a liquid crystal substrate as the above article, in particular a silicon wafer as an example, however, the present invention is not limited to the above article. The container of the present invention is applicable to any kind of article necessary to be kept under the condition of high cleanliness during being transported.
2. Background of the Invention
The semiconductor substrate, in particular silicon wafer is contaminated when dust or vaporized organic compounds (hereinafter referred to as "dust") are attached thereto, thus leading to a lower productivity, i.e., the rate of producing products with high-quality is low. It is therefore necessary to maintain high cleanliness in the surroundings of the silicon wafer when the silicon wafer is transported. More specifically, the silicon wafer is one of the articles necessary to be kept under the condition of high cleanliness during transported (hereinafter referred to as a "detesting dust article").
In general, the silicon wafer is worked in a room where cleanliness is high (hereinafter referred to as a "high cleanliness room"), i.e., so called a clean room. On the other hand, when the silicon wafer is transported, the silicon wafer is received in an airtightly sealed container, the inside of which is kept under the condition of high cleanliness (hereinafter referred to as a "container"), and then, the container with the silicon wafer received therein is transported. Thus, the silicon wafer can be transported through a room in which the degree of cleanliness is low or outdoor (hereinafter referred to as a "low cleanliness room"), avoiding the silicon wafer from being contaminated by dust or the like during transported.
There is disposed a loader having an opening portion, which opening portion can be closed, in the border portion between the high cleanliness room and the low cleanliness room. The silicon wafer is moved through the above loader from the inner space of the container with high cleanliness to the high cleanliness room, then worked therein (hereinafter referred to as "loading"). In addition, the silicon wafer is moved through the loader from the high cleanliness room to the inner space of the container with high cleanliness, then transferred to another treatment step (hereinafter referred to as "unloading").
More specifically, the silicon wafer is loaded or unloaded through the above opening portion of the loader. The container has a cover (i.e., lid) in a direction to the opening portion of the loader, which cover is opened when the silicon wafer is loaded or unloaded.
When the silicon wafer is not loaded or unloaded, the opening portion of the loader is kept closed so as to prevent dust from floating into the high cleanliness room from the low cleanliness room. A door may be disposed in the opening portion so that the opening portion can be opened or closed by the door.
In this case, the door may be large enough to completely close the opening portion of the loader. In addition, the door may be the size in which the door is about 5 mm smaller in each side than the respective side of the opening portion of the loader in such manner that there is provided aperture (open space) between the door and the opening portion of the loader, while the air pressure in the high cleanliness room is kept higher than that in the lower cleanliness room, thus air flows through the aperture from the high cleanliness room to the low cleanliness room.
The following standards for the above container and loader are proposed and applied: SEMI (Semiconductor Equipment and Material International) Standard E47.1 [Box/Pod (FOUP)], E15.1[Tool Load Port], E57[Kinematic Coupling], E62[Front-Opening Interface Standard (FIMS), E63 [Box/Opener to Tool Standard (BOLTS) and the like (hereinafter referred to as "Standard").